It is frequently desirable to press meat while it is being cooked. One of the more common uses for meat presses is in preparing boneless ham. In the process the bone is removed from raw ham leaving a cylindrical hole through the ham. The cylindrical hole is closed by cooking the ham while it is compressed enough so that opposite sides of the hole are brought into contact with each other. During the cooking process protein is released which solidifies between the two contacting faces of the hole causing it to disappear.
The process of cooking ham while it is compressed is usually effected by placing boned raw hams on a supporting tray, usually in the form of a screen, and having a pressing tray exert force on the ham squeezing it between the pressing tray and the supporting tray and cooking the boned ham while it is compressed. Typical meat presses cause force to be exerted by a number of springs connected between the supporting tray and the pressing tray. Employing spring force is very desirable because during the cooking process the hams shrink and springs maintain substantially the same force on the ham during the entire cooking process. The difficulty with using springs is that loading and unloading requires the springs to be expanded which requires the insertion of equipment between the trays and which may result in dangerous release of the springs while a worker's arm is between the trays. It is also diffcult to connect and disconnect multiple springs between the trays and to work between them.
After the presses are loaded with hams, they must be individually placed on a rack or truck by hand. The rack full of hams in their presses is put in an oven or smokehouse, where the hams are cooked. After cooking, the presses must be removed from the rack and opened so that the hams can be removed. Usually the same equipment is used for this re-opening of the presses. During all of these procedures, the presses must be handled by hand. The weight of the hams limits the maximum number which can be placed in a single press to 3 or 4.
The spring-operated devices known to the art are also not adequate because the only way to compensate for smaller-than-usual hams or larger-than-usual hams is to replace the standard springs of the press with larger or smaller springs depending on whether larger or smaller hams are to be cooked.
Other devices have been made which have frames of movable shelves between which hams can be pressed. The shelves are moved by jacks or other positive-displacement mechanisms. This eliminates the handling of individual presses but creates another problem: as the meat shrinks during cooking, the positions of the shelves must be repeatedly adjusted. To do this a worker must enter the oven.